Unlike other processes, the laser beam is able to apply energy to a limited space in order to melt the glass solder precisely, thus generating a bond with long-term, stable hermeticity. The Fraunhofer Institute for Laser Technology ILT is developing the appropriate irradiation strategies and processing heads to achieve this.
Soldered Glass/Glass, Glass/MAM, Glass/Silicon, Glass/LTCC, Glass/ITO components.
Picture Source: Fraunhofer ILT, Aachen
Laser soldered Glass/Silicon sensor package.
Picture Source: Fraunhofer ILT, Aachen
Sensitive component groups such as optical sensors in medical technology, OLED components or dye solar cells require reliable encapsulation so that neither water nor oxygen can reach the interior of the component, thereby possibly impairing its functionality. Conventionally, such components are joined with anodic or glass-frit bonding or they are simply glued together. These bonds, however, are not stable enough over the long term. In addition, the entire component group is heated when it is bonded, which is why the process is not suitable for bonding temperature-sensitive components.
Scientists at the Fraunhofer ILT have developed a process that enables them to reduce the total heating of the component to be encapsulated to a minimum and, thus, prevent thermally induced stress in the process zone. By using laser-based joining with glass solder, the experts in Aachen can hermetically join temperature-sensitive glass/glass as well as glass/ceramics components groups which exhibit long-term stability. They have developed the process to such an extent that large components can also be encapsulated.
Laser-based Joining with Glass Solder
During laser-based glass soldering, the laser beam is guided precisely over the workpiece and applies the energy solely into the glass solder itself to melt it. The substrates to be joined are heated only via heat conduction to wet them; this way, the overall heating of the component group can be reduced to a minimum. An appropriate radiation approach for this is quasi-simultaneous laser soldering: a highly dynamic 2D scanner system guides the laser beam over the solder contour many times at a high speed and evenly heats the entire glass solder contour up to processing temperature by means of a laser power-time profile. After both joining pairs have been bonded, the temperature in the processing zone is lowered according to the profile without creating stress.
The quasi-simultaneous laser soldering is technically restricted by the maximum processing field size of the focusing optics as well as limited, from an economic point of view, by the laser power required, PL>1kW, when substrate sizes of 100 x 100 mm² are joined. Current processing approaches unify the resource-efficient energy input of this quasi-simultaneous process guidance with the size and geometry freedom of continuous processing optics.
New Geometrical Freedom for Temperature-sensitive Component GroupsThe so-called contour soldering with energy input adapted laterally to feed movement enables, for the first time, large substrates to be joined at significantly lower laser power. For contour soldering, continuous beam sources are adequately dimensioned at PL
Viewing the Entire Production Chain
The team at the Fraunhofer ILT will design the entire production chain for its partners. From initial steps to prepare the process, such as the selection of an appropriate glass solder, via the application of the glass solder by means of screen printing all the way to the pre-vitrification of the pairs to be joined in a convection oven. Especially for laser-based glass soldering, the researchers have developed processing heads as well as positioning and clamping technologies to guarantee homogenous and reproducible packaging in either ambient or inert protective gas atmospheres.
Fraunhofer ILT at the Hannover Messe
In Hall 17 at the IVAM joint stand C50.13 at the Hannover Messe from April 8 to 12, 2013, our experts will be exhibiting component groups that were joined using laser-based glass soldering: for example, sensor housings with bonds of glass/silicon and glass/ceramics as well as glass/glass bonds with ITO layers.
ContactsElmar Gehlen, Dipl.-Ing.
Axel Bauer | Fraunhofer-Institut
No compromises: Combining the benefits of 3D printing and casting
23.03.2018 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA
Intelligent wheelchairs, predictive prostheses
20.12.2017 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA
Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.
The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
23.03.2018 | Event News
19.03.2018 | Event News
16.03.2018 | Event News
23.03.2018 | Materials Sciences
23.03.2018 | Agricultural and Forestry Science
23.03.2018 | Physics and Astronomy